Mobile Location Services is the service, which using UE location to carry out, such as emergency rescue etc. Currently, positioning includes the following two methods: the control Plane Location and SUPL (Secure User-Plane Location). The control Plane Location needs to use Evolved Universal Terrestrial Radio Access Network E-UTRAN signaling links, MME (Mobility Management Entity) send positioning requests to E-SMLC (Evolved Serving Mobile Location Center) to trigger positioning process, and after finishing positioning, the positioning results is returned to the MME by the E-SMLC, E-SMLC, MME, eNodeB, and UE etc. may be involved in the positioning process.
As shown in FIG. 1, is a positioning structure diagram related to E-UTRAN, it comprises E-SMLC, SLP (SUPL Location Platform), MME, eNodeB and UE. Therein,
E-SMLC, is used for transforming the location which the user required into the corresponding E-UTRAN measurement parameter, and selecting the positioning method; calculating the final results and the accuracy of the returned location.
MME, is used for providing mobility management for LCS (Location Service), comprising reporting UE mobility to E-SMLC/GMLC (Gateway Mobile Location Center).
eNodeB, is used for providing the related measurement results of positioning services to E-SMLC, and transmitting the auxiliary information which positioning services needed.
UE, is used for providing the related measurement results of positioning services to E-SMLC.
In the present LTE (Long Term Evolution) system, the methods of positioning based on control plane location comprises: CELL ID+TA (Timing Advance)+AOA (Angle of Arrival) scheme, OTDOA (Observed Time Difference Of Arrival), and A-GNSS (Advance Gateway Navigation Satellite System) etc., for calculating the location of UE, these schemes need to acquire the cell antenna location information.
Therein, the fundamental of CELL ID+TA+AOA scheme is: calculating the location, by acquiring the angle between the direction of UE to the eNodeB (base station) and the true north (AOA), and acquiring Timing Advancement of UE (TA). In LTE, TA can be maintained by UE, or ban be acquired by base station measurement.
eNodeB get the transmitting signal AOA by the smart antenna, UE is on the ray which is the Node B as a starting point, and the angle of ray direction counterclockwise rotation from the north is AOA.
UE-side timing is shown in FIG. 2, the timing offset between up and downlink wireless frame is NTA.
UE side timing is shown in FIG. 3, it can be considered that in general, NTA always reflects twice the delay caused by the distance d. According to NTA, it can be calculated the distance between the UE and the eNode B. As shown in FIG. 4, UE is in the circle which the eNode B is as the center and the distance is as the radius. According to the above information and the serving cell location information, E-SMLC can calculate the location of UE.
However, the current CELL ID+TA+AOA positioning scheme is lack of methods to acquire the servicing cell location information, and thus can not be calculated the location of UE according to the servicing cell location information.